Nonionic detergent mixtures based on specific mixed ethers

ABSTRACT

A nonionic detergent mixture containing 
     a) an ether corresponding to formula (I): 
     
         R.sup.1 O(CH.sub.2 CH.sub.2 O).sub.m R.sup.2               (I) 
    
      in which R 1  is an aliphatic linear alkyl or alkenyl radical containing 12 to 18 carbon atoms, R 2  is an alkyl radical containing 1 to 4 carbon atoms or a benzyl radical and m is a number of 5 to 15, and 
     b1) an ether selected from the group consisting of an ether corresponding to formula (II): ##STR1##  in which R 3  is an aliphatic, linear or branched alkyl radical containing 8 to 10 carbon atoms, R 4  is an alkyl radical containing 1 to 4 carbon atoms or a benzyl radical, p is a number of 2 to 3 and q is a number of 8 to 15 and 
     b2) an ether corresponding to formula (III): ##STR2##  in which R 5  is an aliphatic, linear alkyl radical containing 12 to 14 carbon atoms, R 6  is an alkyl radical containing 1 to 4 carbon atoms or a benzyl radical, x is a number of 0.5 to 2 and y is a number of 5 to 10.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to nonionic detergent mixtures based on selectedmixed ether types and to their use for the production of surface-activeformulations.

2. Discussion of Related Art

The presence of foam is extremely undesirable in a number of industrialprocesses. For example, both in the machine washing of beer bottles ormilk bottles and in the spray cleaning of automobile panels, it is notonly the cleaning or degreasing effect of the surface-activeformulations used which is crucial, the avoidance of form which canseverely impair the operation of equipment is equally important. This isall the more so insofar as highly active but also high-foaming anionicsurfactants are used in many cases.

The problem of foam regulation has certainly been known for some timewith the result that several more or less convincing solutions are knownfrom the prior art. These known solutions may be divided into twogroups:

The first group comprises processes involving the addition of defoamerswhich are often paraffinic hydrocarbons or silicone compounds. In mostcases, however, this is undesirable for the described applications. Thesecond group of processes involves the use of surface-activeformulations which are themselves low-foaming and which, optionally,many also exhibit defoaming properties. The surface-active formulationsin question are generally nonionic surfactants or surfactant-likesystems such as, for example, fatty alcohol propylene glycol ethers orblock polymers of ethylene and propylene glycol which, unfortunately,are not sufficiently biodegradable.

End-capped fatty alcohol polyglycol ethers, so-called "mixed ethers",which are described for example by R. Piorr in Fat. Sci. Technol. 89,106 (1987), have established themselves on the market as particularlyeffective low-foaming surfactants.

The use of mixed ethers as low-foaming surfactants has also beenextensively described in the patent literature. For example, EP-A 0 124815 (Henkel) describes mixed ethers containing 8 to 18 carbon atoms inthe fatty alkyl chain and 7 to 12 ethylene oxide units in the polyetherchain as foam-suppressing additives for low-foaming cleaningformulations. Octyl and/or decyl mixed ethers containing 3 to 4 ethyleneoxide units are proposed for the same purpose in EP-B 0 303 928(Henkel).

According to EP-A 0 180 081 (BASF), mixed ethers containing 6 to 12carbon atoms in the fatty alkyl chain and EO/PO/EO blocks in thepolyether chain may be used for suppressing foam in the processing offoods and in fermentation processes. According to the teaching of EP-B 0324 340 (Henkel), mixed ethers containing 6 to 28 carbon atoms in thefatty alkyl chain and 2 to 10 ethylene oxide units in the polyetherchain may be used for the same purpose. In addition, DE-A 39 28 600(Henkel) describes nonionic surfactant mixtures containingnon-end-capped fatty alcohol polyalkylene glycol ethers in addition tovarious types of mixed ethers.

EP-A 0 420 802 (Ciba-Geigy) describes wetting agents containingopen-chain and/or end-capped fatty alcohol polyglycol ethers for thepretreatment of textiles. Starting materials containing a fatty alkylchain of at least 8 and preferably 9 to 14 carbon atoms and 2 to 24 andpreferably 4 to 8 alkylene oxide units in the polyether chain aredisclosed as suitable; they may have open chains or may be end-capped bya C₁₋₈ alkyl group, a cycloaliphatic radical containing at least 5carbon atoms or a phenyl lower alkyl or styryl group. The only Examplerefers solely to the use of an open-chain adduct of 15 moles of alkyleneoxide with a C₉₋₁₁ oxoalcohol.

Finally, mixed ethers based on linear fatty alcohol PO EO adducts whichcontain 8 to 10 carbon atoms in the fatty alkyl chain, 0.5 to 2 moles ofpropylene oxide and 7 to 9 moles of ethylene oxide in the molecule andwhich are end-capped by a C₁₋₄ alkyl radical are known from DE-C1 42 43634 (Henkel).

A particular problem involved in the optimization of mixed ethers is tobalance the need for products with excellent performance properties onthe one hand and high ecotoxicological compatibility on the other hand.In specific terms, a particular problem addressed by the presentinvention was to mix mixed ethers in such a way that the mixtures wouldnot only show favorable cleaning and foaming properties, they would alsobe readily biodegradable and would show low toxicity towards aquaticbiocoenoses (LC₅₀ >1 mg/l).

DESCRIPTION OF THE INVENTION

The present invention relates to nonionic detergent mixtures containing

a) mixed ethers corresponding to formula (I):

    R.sup.1 O(CH.sub.2 CH.sub.2 O).sub.m R.sup.2               (I)

in which R¹ is an aliphatic linear alkyl and/or alkenyl radicalcontaining 12 to 18 carbon atoms, R² is an alkyl radical containing 1 to4 carbon atoms or a benzyl radical and m is a number of 5 to 15, and

b1) mixed ethers corresponding to formula (II): ##STR3## in which R³ isan aliphatic, linear or branched alkyl radical containing 8 to 10 carbonatoms, R⁴ is an alkyl radical containing 1 to 4 carbon atoms or a benzylradical, p is a number of 2 to 3 and q is a number of 8 to 15, and

b2) mixed ethers corresponding to formula (III): ##STR4## in which R⁵ isan aliphatic, linear alkyl radical containing 12 to 14 carbon atoms, R⁶is an alkyl radical containing 1 to 4 carbon atoms or a benzyl radical,x is a number of 0.5 to 2 and y is a number of 5 to 10.

It has surprisingly been found the surfactant mixtures according to theinvention not only show excellent performance properties, they alsoexceed a value of 60% in their ultimate biological degradation and havea toxicity towards aquatic biocoenoses (LC₅₀ value) above 1 mg/l.Accordingly, the surfactant mixtures may be classified as readilybiodegradable and as showing low aquatic toxicity.

Mixed Ethers

Mixed ethers are known substances which may be obtained by the relevantmethods of preparative organic chemistry. They are normally prepared byWILLIAMSON's ether synthesis in which fatty alcohol polyglycol ethersare condensed with alkyl halides in the presence of strong bases.Processes for their production are known, for example, from DE-OS 28 00710 (Kuraray) and DE-C1 37 44 525 (Henkel). In addition, an overview byPiorr et al. on the subject of "mixed ethers" can be found in Fat Sci.Technol. 89, 106 (1987).

Typical examples of mixed ethers which may be used as component

a) of the mixtures according to the invention are methyl-, ethyl- orbutyl-end-capped adducts of 5 to 15 moles and preferably 8 to 12 molesof ethylene oxide with linear cocofatty alcohols containing 12 to 18 andpreferably 12 to 14 carbon atoms. A C_(12/18) cocofatty alcohol 10 EOn-butyl ether (Dehypon® LT104, Henkel KGaA, Dusseldorf, FRG) isparticularly preferred.

Component b1) may be selected, for example, from methyl-, ethyl- orbutyl-end-capped adducts of, on average, first 2 to 3 moles of propyleneoxide and then 8 to 15 moles of ethylene oxide with primary alcoholscontaining 8 to 10 carbon atoms. C_(8/10) 1.3 PO 9 EO n-butyl ether,2-ethylhexyl 1.5 PO 10 EO n-butyl ether or isodecyl 1.3 PO 8 EOtert.butyl ether, for example, is particularly preferred.

Component b2) may be selected, for example, from methyl-, ethyl- orbutyl-end-capped adducts of, on average, first 0.5 to 2 moles ofpropylene oxide and then 5 to 10 moles of ethylene oxide with fattyalcohols containing 12 to 14 carbon atoms. Atypical example is C_(12/14)1.3 PO 9 EO n-butyl ether.

The nonionic detergent mixtures according to the invention may containcomponents a) and b) in a ratio by weight of 25:75 to 75:25 andpreferably in a ratio by weight of 40:60 to 60:40. The ratio ofcomponent b1) to component b2) may be from 0:100 to 100:0 and ispreferably from 25:75 to 75:25.

Other Nonionic Ingredients

In addition to the above-mentioned mixed ethers corresponding toformulae (I) to (III), the nonionic detergent mixtures according to theinvention may contain other mixed ethers corresponding to formula (IV):

    R.sup.7 O(CH.sub.2 CH.sub.2 O).sub.n R.sup.8               (IV)

in which R⁷ is an aliphatic branched alkyl radical containing 8 to 18carbon atoms, R⁸ is an alkyl radical containing 1 to 4 carbon atoms or abenzyl radical and n is a number of 5 to 15. Examples of these othermixed ethers are methyl-, ethyl- or butyl-end-capped adducts of, onaverage, 5 to 15 moles of ethylene oxide with oxoalcohols containing 8to 18 carbon atoms. A typical example is isotridecyl 10 EO n-butylether. The percentage content of mixed ethers corresponding to formula(IV) may be from 10 to 40% by weight, based on the mixture.

In addition, the detergent mixtures according to the invention maycontain fatty alcohol polyglycol ethers corresponding to formula (V):

    R.sup.9 O(CH.sub.2 CH.sub.2 O).sub.z H                     (V)

in which R⁹ is an alkyl radical containing 12 to 14 carbon atoms and zis a number of 2 to 4. Typical examples are adducts of, on average, 2 to4 moles of ethylene oxide with fatty alcohols containing 12 to 14 carbonatoms, such as for example C_(12/14) cocoalkyl 3 EO adduct. Thepolyglycol ethers may have a conventional homolog distribution althoughthey preferably have a narrow homolog distribution. The percentagecontent of fatty alcohol polyglycol ethers corresponding to formula (V)may be from 10 to 40% by weight, based on the mixture.

Commercial Applications

The nonionic detergent mixtures according to the invention aredistinguished by excellent performance properties, are readilybiodegradable and show low aquatic toxicity.

Accordingly, the present invention also relates to the use of thenonionic detergent mixtures according to the invention for theproduction of surface-active formulations, more especially rinse aids,cleaning formulations for hard surfaces and defoamers for detergents.

The following Examples are intended to illustrate the invention withoutlimiting it in any way.

Examples I. Wetting Power

Wetting power was determined by the immersion wetting method using 1 gof active substance/l, 20° C., in water with a hardness of 16° d.Particulars of this method can be found in Tens. Surf. Det. 27, 243(1990). The wetting time t_(n) was determined in s. The results are setout in Table 1.

II. Foaming Power

Foaming power was determined by the foam generation method using 1 g ofactive substance/l, 20° C., in water with a hardness of 16° d.Particulars of this method can be found in Tens. Surf. Det. 27, 243(1990). The basic foam (t-0) and the foam collapse after 5 minutes in mlwere determined. The results are set out in Table 1.

III. Ultimate Biological Degradation

Biological degradability was determined by the Closed Bottle Test. Thedegradation rate (BOD/COD) after 30 days was determined. Particulars ofthis test can be found in Fette, Seifen, Antstrichmitt., 87, 421 (1985).The results are set out in Table 2.

IV. Aquatic Toxicity

Aquatic toxicity was determined against fish (carp), daphniae and algae.It is expressed as the LC₅₀ value, i.e. the lethal concentration for 50%of the population. The results are set out in Table 3.

                  TABLE 1                                                         ______________________________________                                        Wetting and foaming power                                                           PC                               t.sub.n                                Ex.   %        R       PO    EO  EC    s   S.sup.0                            ______________________________________                                        1     50       n-16/18 --    10  4     20  0                                        50       i-13    --    10  4                                            2     50       n-12/18 --    10  4     20  0                                        50       i-13    --    10  4                                            3     40       n-12/18 --    10  4     22  0                                        60       n-8/10  2     10  4                                            4     40       n-12/18 --    10  4     21  0                                        30       i-13    --    10  4                                                  30       n-12/14 1     10  4                                            C1    100      n-12    --     8  4     28  0                                  C2    100      i-13    --    10  4     21  0                                  ______________________________________                                         Legend:                                                                       PC = percentage content in the detergent mixture                              R = alcohol radical                                                           PO = propylene oxide groups                                                   EO = ethylene oxide groups                                                    EC = end capping                                                              t.sub.n = wetting time                                                        S.sup.0 = basic foam                                                     

                  TABLE 2                                                         ______________________________________                                        Biological degradability                                                      Percentages as % by weight                                                    Ex.    PC %    R        PO   EO   EC                                                                                  ##STR5##                              ______________________________________                                        5       50     n-16/18  --   10   4    >60                                            50     i-13     --   10   4                                           6       50     n-12/18  --   10   4    >60                                            50     i-13     --   10   4                                           7       40     n-12/18  --   10   4    >60                                            60     n-8/10   2    10   4                                           8       40     n-12/18  --   10   4    >60                                            30     i-13     --   10   4                                                   30     n-12/14  1    10   4                                           C3     100     n-12     --    8   4    >60                                    C4     100     i-13     --   10   4    <60                                    ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                        Toxicity towards aquatic organisms                                                                                F.    D.    A.                                PC                              LC.sub.50                                                                           LC.sub.50                                                                           LC.sub.50                     Ex. %       R        PO   EO   EC   mg/l  mg/l  mg/l                          ______________________________________                                         9  50      n-16/18  --   10   4    >1    >1    >1                                50      i-13     --   10   4                                              10  50      n-12/18  --   10   4    >1    >1    >1                                50      i-13     --   10   4                                              11  40      n-12/18  --   10   4    >1    >1    >1                                60      n-8/10   2    10   4                                              12  40      n-12/18  --   10   4    >1    >1    >1                                30      i-13     --   10   4                                                  30      n-12/14  1    10   4                                              C5  100     n-12     --    8   4    <1    <1    <1                            C6  100     i-13     --   10   4    >1    >1    <1                            ______________________________________                                         Legend:                                                                       F = fish                                                                      D = daphniae                                                                  A = algae                                                                

What is claimed is:
 1. A nonionic detergent mixture comprisinga) anether corresponding to formula (I):

    R.sup.1 O(CH.sub.2 CH.sub.2 O).sub.m R.sup.2               (I)

in which R¹ is an aliphatic linear alkyl or alkenyl radical containing12 to 18 carbon atoms. R² is an alkyl radical containing 1 to 4 carbonatoms or a benzyl radical and m is a number of 5 to 15, and b); b1) anether corresponding to formula (II): ##STR6## in which R³ is analiphatic, linear or branched alkyl radical containing 8 to 10 carbonatoms, R⁴ is an alkyl radical containing 1 to 4 carbon atoms or a benzylradical, p is a number of 2 to 3 and q Is a number of 8 to 15 and b2) anether corresponding to formula (III): ##STR7## in which R⁵ is analiphatic, linear alkyl radical containing 12 to 14 carbon atoms, R⁶ isan alkyl radical containing 1 to 4 carbon atoms or a benzyl radical, xis a number of 0.5 to 2 and y is a number of 5 to 10, wherein componentb1) and component b2) are present in a ratio by weight of 25:75 to75:25.
 2. A nonionic detergent mixture as in claim 1 wherein componenta) and component b) are present in a ratio by weight of 25:75 to 75:25.3. A nonionic detergent mixture as in claim 1 further containing anether corresponding to formula (IV):

    R.sup.7 O(CH.sub.2 CH.sub.2 O).sub.n R.sup.8               (IV)

in which R⁷ is an aliphatic branched alkyl radical containing 8 to 18carbon atoms, R⁸ is an alkyl radical containing 1 to 4 carbon atoms or abenzyl radical and n is a number of 5 to
 15. 4. A nonionic detergentmixture as in claim 1 further containing a fatty alcohol polyglycolether corresponding to formula (V):

    R.sup.9 O(CH.sub.2 CH.sub.2).sub.z H                       (V)

in which R⁹ is an alkyl radical containing 12 to 14 carbon atoms and zis a number of 2 to
 4. 5. A nonionic detergent mixture as in claim 1wherein component a) comprises a C₁₂ -C₁₈ cocofatty alcohol n-butylether containing 10 moles of ethylene oxide.
 6. A nonionic detergentmixture as in claim 1 wherein component b1) is selected from the groupconsisting of a C₈ -C₁₀ alkyl radical n-butyl ether containing 1.3 molesof propylene oxide and 9 moles of ethylene oxide; a C₈ -C₁₀ alkylradical 2-ethylhexyl n-butyl ether containing 1.5 moles of propyleneoxide and 10 moles of ethylene oxide; and a C₈ -C₁₀ alkyl radicalIsodecyl tertiary butyl ether containing 1.3 moles of propylene oxideand 8 moles of ethylene oxide.
 7. A nonionic detergent mixture as inclaim 1 wherein component b2) comprises a C₁₂ -C₁₄ alkyl radical n-butylether containing 1.3 moles of propylene oxide and 9 moles of ethyleneoxide.